Safety switch cutoff control



Oct 21, 1969 Q DELANEY 3,474,317

SAFETY SWITCH CUTOFF CONTROL Filed March 7. 1967 3 Sheets-Sheet l I .L 0 a) INVENTOR. H6. 4 7 6942155 6'. O'A/M/f) Oct. 21, 1969 Filed March 7. 1967 C. E. DELANEY SAFETY SWITCH CUTOFF CONTROL 3 Sheets-Sheet 2 INVENTOR. CWAEMS flflAA/fy ATTOB/VfYS Oct. 21, 1969 c. E. DELANEY 3,474,317

SAFETY swncn CUI'OFF CONTROL Filed March '7. 1967 3 Sheets-Sheet 5 wig United States Patent US. Cl. 318-266 5 Claims ABSTRACT OF THE DISCLOSURE A mechanized apparatus for opening and closing an upwardly actuated door comprising a beam normally mounted in a horizontal position above the door and including an endless flexible element extending around pulleys connected to a reversible motor. The endless element is connected to the door for moving same along guide tracks extending between the open and closed positions. The motor, which may be directly or remotely controlled, is energized through switch mechanisms which are automatically actuated to reverse the movement of the door if it engages an obstacle during all but a small part of its movement in the closing direction. However, during the latter part of its closing movement, engagement of the door with an object merely stops the door without reversing its direction of movement.

Persons acquainted with the operation of upwardly actuated doors having an electrical mechanism for effecting their movement are generally aware that some door operators have a safety switch whereby the direction of door movement is automatically reversed if the door engages an obstruction during its movement, particularly when such movement is in a downward or closing direction. This safety feature has been provided to prevent damage to equipment and injury to personnel which might result from inadvertent operation of the door when such objects are in the path of movement.

Door operators of this general character are often provided with switch means which prevent the door from reversing its direction of movement when the lower edge of the door bumps against the threshold. However, such switch means must "be carefully set so that it operates just slightly before the door reaches the closed position. Otherwise, if the door strikes an object after the switch means is opened, the motor will continue to drive the door towards the closed position, with the possibility of damage to the door or operator.

In view of the close setting or timing of the switches used in existing operators, any small or thin object engaged by the door, even though the object may only be an inch or two in thickness, will promptly reverse the doors movement and send it back to its starting position. In certain geographical regions, such as the northern part of the United States, it is not common for snow and ice to build up quickly to the thickness of several inches directly in the path of the door if the door remains open for a relatively short period of time. Moreover, extremely cold or extremely hot weather will sometimes cause the material forming the apron or threshold of the door opening to expand or heave upwardly as much as an inch or more and thereby cause a reversing movement of the door into its :fully open position.

Under all of the foregoing circumstances, it would be far preferable to have the door stop at the point of contact with the obstruction, be it snow, a childs toy or a distorted threshold, even though there might be a space of an inch or two open between the threshold and part of the lower edge of the door. In this position, the door would at least block the entrance of most of the bad weather or prevent trespassers from entering.

Patented Oct. 21, 1969 There are times when a door will engage an obstruction while it is being opened. In such case, it is at least desirable that the door should continue its movement in the opening direction after such a temporary stop. That is, even though the door will reverse its direction and move to the open position after it is stopped by a safety switch while being closed, it is not desirable to have the reverse situation, namely, to have the door return to the fully closed position after it has been stopped by an obstruction while being opened. For one reason, where the door can be operated by a remotely controlled radiofrequency signal, it would be possible for a stray signal of the same frequency to reverse the door movement after the emergency stop and while the object is still beneath the door.

It is possible for a relay in the remote transmitter to hang up in the closed position, or for the inexperienced person to continue to hold the manual switch in the closed position throughout the cycle of the closing operation of existing operators. It is, therefore, desirable to have a switching mechanism which must first be fully released (or opened) and then close for a second time before the door will reverse its direction of movement. Moreover, it is desirable that the switching mechanism be arranged so that the door will then open fully and come to a stop in the open position. On the other hand, if the door is stopped during its opening movement by an obstruction, then it is desirable that repeated operations of the manual switch or remote relay will merely cause the door to first stop and then move upwardly in small increments until it reaches the fully opened position before it can be reversed in its direction of movement toward the closed position.

Accordingly, the objects and purposes of the invention have been to provide a switch circuit and mechanism for a motorized door opener capable of overcoming the problems and achieving the results set forth above.

A further object of the invention has been the provision of a switch circuit and mechanism, as aforesaid, which is completely foolproof in operation, which is simple in construction, which can be adapted to existing circuits and mechanisms for effecting motorized operation of doors and which does not interfere in any way with the normal, manual or remote controls conventionally used for energizing the electrical system whereby the door is opened or closed.

Other objects and purposes of this invention will become apparent to persons familiar with this type of equipment upon reading the following specification and examining the accompanying drawings, in which:

FIGURE 1 is a broken, sectional view of an upwardly acting door in combination with a motorized door operator embodying the switch circuit and mechanism of the invention.

FIGURE 2 is a broken, sectional view taken along the line IIII in FIGURE 1 with the switch box cover removed. 7

FIGURE 3 is a sectional view taken along the line IIIIII in FIGURE 2.

FIGURE 4 is a sectional view taken along the line IV'IV in FIGURE 2.

FIGURE 5 is a sectional view taken along the line VV in FIGURE 2.

FIGURE 6 is a broken, sectional view taken along the line VI-VI in FIGURE 2.

FIGURE 7 is a perspective view of a part of the switch mechanism shown in FIGURE 2.

FIGURE 8 is a diagrammatic sketch of the switch circuit with which the switch mechanism of the invention is combined.

For convenience in description, the terms inner, outer and derivatives thereof will have reference to 3 the portion of the structure appearing in FIGURE 2. Also for convenience, the terms upper, lower, front, rear and words of similar import will have reference to the structure appearing in FIGURE 1, it being understood that the rear of such structure will normally be positioned at the left end of FIGURE 1.

DETAILED DESCRIPTION The objects and purposes of the invention, including those set forth above, have been met by providing an electric motor driven operator (FIGURE 1), which may be manually or remotely controlled, for opening and closing an upwardly acting door 11. One such door, known as the Overhead Door, is comprised of several horizontally hinged section-s having rollers 12 mounted thereon for engagement with side rails 13 for guiding the movement of the door between a substantially vertical closed position and a substantially horizontal open position. However, the invention can be readily adapted to other types of doors and other patterns of door movement. The door 11 is designed to cover an opening 14 having a threshold 16.

The operator 10 (FIGURE 1) includes an elongated beam 17 having a pair of slide rails 18 and 19 between which the shuttle 22 is supported for movement lengthwise thereof. Said shuttle 22 is pivotally connected by an arm 23 to the door 11 for effecting upward and downward movement thereof in response to left or rearward and right or frontward movement, respectively, of the shuttle 22. The operator 10 has a drive shaft 24 (FIG- URE 2) which is rotatably supported upon the beam 17 by bearings 26 and 27 mounted upon the side wall 28 of the switch box 43 and the bearing bracket 29, respectively, near the rearward end of the beam, remote from the door opening 14. A drive pulley 32 (FIGURE 2) is supported upon the shaft 24 adjacent the bearing 27 and is connected by a belt 33 (FIGURE 1) to a pulley, not shown, on the motor 34.

A sprocket 37 (FIGURE 2) is secured upon the shaft 24 for engagement with a chain 38 which is connected at its opposite ends to the opposite ends of a cable 39' that extends around the pulley 42 supported upon the front end of the beam 17, adjacent the door opening 14. Two corresponding ends of the chain 38 and cable 39 are interconnected by mutual engagement with the shuttle 22. Accordingly, as the cable and chain are moved around the sprocket and pulley 37 and 42, respectively, the shuttle 22 is moved lengthwise of the slide rails 18 and 19, whereby the door 11 is opened or closed. The lengths of the chain and cable are selected so that the chain is always in engagement with the sprocket 37 and the cable is always in engagement with the pulley 42 throughoutthe full movement of the shuttle 22.

The drive shaft 24 extends into the switch box 43 (FIG- URE 2) where it is threaded substantially the full length thereof and threadedly supports a pair of switch actuating nuts 45 and 46 having a plurality of closely spaced slots 47 and 47A, respectively, in the peripheral portions thereof. A U-shaped timing bar 48 is pivotally supported upon and between the side walls 28 and 51 of the switch box 43, and it is resiliently urged by the spring 52 into a pair of the slots 47 and 47A in said nuts 45 and 46 for preventing rotation of said nuts when the shaft 24 is rotated. Thus, rotation of shaft 24 causes said nuts to move lengthwise of the shaft 24.

As shown in FIGURE 3, the chain 38 engages an idler sprocket 53 supported by a bracket 54 on the safety switch actuating member 56 which is pivotally mounted upon the beam 17 near to the switch box 43 for movement substantially around an axis parallel with the drive shaft 24. A bolt 57 loosely extends through an opening in a plate 58 on the rail 19 and through an opening in the lower end of the actuating member 56 after which it is engaged by a wing nut 59. A spiral spring 62 is sleeved upon the bolt 57 between the actuating member 56 and the wing nut 59 whereby said actuating member is resiliently urged against the plate 58.

As appearing in FIGURE 3, the chain 38 moves in direction D when it is urging the door 11 (FIGURE 1) in a downward direction. However, if the door encounters an obstruction which interrupts such downward movement, the chain cannot continue to move around the drive sprocket 37, as urged by the shaft 24. Consequently, the tension applied by the drive sprocket 37 to the chain 38 will tend to straighten out the bend in the chain where it passes partially around the idler sprocket 53, whereby the actuating member 56 is moved leftwardly (FIGURE 3) against the contrary urging of the spring 62. A stop 63, which may be a headed pin connected to the rail 18 (FIGURE 4) and extending through an opening 64 (FIGURE 2) in the actuating member 56, is arranged so that the head 66 thereof will positively stop movement of the actuating member 56 at a predetermined distance from the beam 17 to protect the ele-- ments engaged and operated thereby. The hinged movement of the actuating member 56 can also be controlled by increasing the tension on the spring 62.

A pair of limit switches 67 and 68 (FIGURE 2) are mounted within the switch box 43 on the front side of the shaft 24, and they have switch actuators 71 and 72, respectively, which are engageable by the nuts 45 and 46. As shown in FIGURE 8, the normally closed switches 67 and 68 are arranged in series with the forward and reverse circuits of the reversible motor 34 to disconnect the motor from its source of potential when the door reaches its fully open or fully closed poistion. The opening of the switches 67 and 68 can be accurately set by appropriate adjustment of the nuts 45 and 46 along the shaft 24.

The electrical circuit of the operator 10 (FIGURE 8) also includes a relay coil 73 connected in series with the secondary of the transformer 74 and a normally open, manually operable pushbutton switch 76. The coil 73 operates an armature 77 which is arranged to reverse the flow of current through the field of the motor 34 and thereby reverse the rotation of the motor. The armature 77 also connects a lamp 78 in parallel with the motor 34 while it is operating in the door opening direction.

The normally open safety switch 79 (FIGURES 2 and 8) has a switch actuator 82 (FIGURE 2) which, when engaged by the actuator member 56, closes the safety switch 79, which is in parallel with the normally open pushbutton switch 76. Accordingly, if the door 11 strikes an obstruction as it is moving upwardly or downwardly, except when the door is close to the threshold 16, the safety switch 79 is closed, thereby energizing the relay coil 73 whereby the armature 77 is shifted to the opposite position and, accordingly, the rotational direction of the motor, hence, the direction of the movement of the door, is reversed.

The threshold 16 (FIGURE 1) of the opening 14 constitutes an obstruction to movement of the door 11 and it would be undesirable to have the door reverse its direction of movement upon an engagement of the threshold by the resilient sealing element 83 on the lower edge of the door. Accordingly, a normally closed, safety switch cutoff switch 84 (FIGURES 2 and 8) is connected in series with the safety switch 79 and is positioned within the switch box 43 (FIGURE 2) so that its actuating arm 86 is engaged by nut 46 to open the switch 84 just before the door 11 reaches the lowest point in its downward movement, as determined by the opening of the limit switch 68 by nut 46.

As stated above, there are certain types of obstructions which are relatively close to the ground and which do not warrant reopening of the door when they are engaged by the door, particularly during inclement weather. Accordingly, it is desirable to open the limit switch 68 if such an obstruction is engaged by the door when it is relatively close to the threshold 16, but before the limit switch 68 would normally be opened by the nut 46 (FIG- URE 2). This is accomplished by the linkage including the rocker arm 87 (FIGURES 6 and 7) and the trigger 88 (FIGURES 5 and 7), which open the limit switch 68 if downward movement of the door is obstructed during a predetermined, final portion of such movement, just before the door is closed.

Specifically, the rocker arm 87 (FIGURE 2) has between the ends thereof a frontwardly extending flange 91 which is pivotally supported upon the screw 92 within the switch box 43 at a point between the switches 67 and 68. Said rocker arm 87 has a pair of integral elements 93 and 94 which project in a direction substantially parallel with the axis of the screw 92 on opposite sides of the flange 91. The element 93 is located near the leftward end of the rocker arm 87 and is disposed between the switch actuator 71 and the switch 67 so that the leftward end of the arm 87, as appearing in FIGURE 2, is moved upwardly by the switch actuator 71 when said switch 67 is opened by the nut 45. The element 94 is disposed upon the rearward (or lower) side of the switch actuator 72 so that it causes the actuator 72 to open the switch 68 when the rightward end of the arm 87 is moved upwardly by the spring 96, which is held under compression between the rightward end of the arm 87 and the casing of cutoff switch 84.

The trigger 88 (FIGURES 4 and 5) is pivotally supported by means of the pin 97 upon the bracket 98 which is secured to the switch 68 by a screw 99. The front (or upper) end of the trigger 88 has a sidewardly extending flange 102 (FIGURE 2) which is engageable by a tab 103 on the adjacent end of the actuating member 56. A leaf spring 104 (FIGURE 5), which is gripped betweenthe bracket 98 and the bracket 85 supporting the switch 68 engages the flange 102 for the purpose of urging same, hence, the upper end of the trigger 88 toward the rail 18.

The lower edge 106 (FIGURE 4) of the trigger 88 is arranged and constructed so that it is engageable by the rightward end (FIGURE 2) of the arm 87 when the actuating member 56 is in its normal position adjacent the rail 18, as shown in FIGURE 4. However, when the actuating member 56 is moved away from the rail 18, as by an interruption in the movement of the chain 38 while the shaft 24 is being driven by the motor 34, the trigger 88 is pivoted as shown in FIGURE 5 so that the lower edge 106 thereof is moved out of a position of engagement with the arm 87 so that said arm can be moved by spring 96 from the solid line position to the broken line position thereof in FIGURE 5. As a result, the element 94 (FIGURE 2) on said arm 87 moves the switch actuator 72 upwardly and thereby opens the limit switch 68.

It will be apparent that the linkage including the rocker arm 87 and trigger 88 will not produce the desired results, namely, to merely stop the downward movement of the door, instead of stopping and reversing the movement of the door, unless the trigger 88 is tripped after the cutoff switch 84 is opened. To achieve the desired result, the switch 84 is positioned leftw-ardly of limit switch 68 (FIGURE 2) so that switch 84 is opened by nut 46 when the door reaches a position approximately six to eight inches from the ground in a preferred arrangement. Thus, when the door is above this level, if the door strikes an obstruction during its downward'movement, stoppage of the door by the, obstruction will cause the trigger 88 to be tripped whereby spring 94 will pivot arm 87 counterclockwise (FIGURE 2) to open the down limit switch 68. Stoppage of the door will also cause the switch 79 to be closed to energize the coil 73 and move the armature 77 to its dotted position, whereby motor 34 is energized in the reverse direction to move the door upwardly toward its open position.

During the downward movement of the door, after the door reaches the point at which the switch 84 is opened, closure of the safety switch 79 by the actuating member 56 will have no effect upon the relay coil 73 because the switch 84 in series therewith will already be open. However, operation of the actuating member 56 will pivot the trigger 88 from its position of FIGURE 4 into its position of FIGURE 5 whereby the arm 87 will be pivoted in a counterclockwise direction (FIGURE 2) by the spring 96, and thereby immediately open the switch 68 which de-energizes the motor 34. Reference is made to a nonreversing range of six to eight inches for illustrative purposes, only.

It will be seen that if the door 11 is obstructed in its upward movement, during the first six or eight inches thereof from its fully closed position, while the cutoff switch 84 is still open, the circuit energizing the motor 34 will not be opened because the limit switch 67 is not opened by the arm 87. Thus, if the door has frozen in a closed position, damage to the equipment is avoided by the opening of the overload switch on the motor.

If the trigger 88 is operated by the actuating member 56 while the door is moving either downwardly or upwardly within the six to eight inch range adjacent the fully closed position, operation of the pushbutton switch 76 or any other normal means for energizing the motor 34, cannot cause the door to move in the closed direction until the door has reached its fully open position and the rocker arm 87 has been recocked by movement of the nut 45 into its FIGURE 2 position, whereby the trigger 88 can be moved by the spring 104 back into its cocked position of FIGURE 4. This results from the fact that the spring 96 will hold the rightward end of the rocker arm 87 in a raised position, where it will hold the switch 68 open, until said cocking of the rocker arm 87 is effected.

OPERATION While the operation of the above-described door operator embodying the invention may be evident from such description, the following disclosure of the operation is given for further clarification. With the door 11 in the closed position of FIGURE 1, the operator may be energized for the purpose of opening or raising the door by manually closing the pushbutton switch 76 (FIGURE 8) whereby the armature 77 is shifted into the broken line position wherein current flows through the normally closed limit switch 67. Thus the motor 34 is energized to move the shuttle 22 (FIGURE 1) rearwardly and, in so doing, raises the door 11. If, during the first six or eight inches of such movement, the door is obstructed, the motor will attempt to continue such movement and, failing to do so, will open the overload switch of the motor in a conventional manner, whereby the motor is de-energized.

If the upward movement of the door 11 is obstructed after it exceeds a height of said six to eight inches, when the safety cutoff switch 84 is closed, the safety switch 79 will be closed and tend to reverse the movement of the door back toward its closed position, However, stoppage of the door also trips the trigger 88 so that arm 87 is moved to open the switch 68. Thus, interruption of the upward movement of the door above the six to eight inch level will stop the door, by shifting the armature 77 into its solid line position of FIGURE 8, but will not reverse the door because the switch 68 is still held open by the rocker arm 87, thereby de-energizing the motor 34. Moreover, when the pushbutton switch 76 is closed again, the armature 77 will move to its broken line position of FIGURE 8, whereby the motor 34 will be energized to continue the opening movement of the door, which movement will continue until the nut 45 has opened the limit switch 67 and, by engagement between the switch actuator 67 and the element 93 on the arm 87, recocked the arm 87 into its FIGURE 2 position,1 whereupon the limit switch 68 is again permitted to c ose.

If, while the door is being closed, it encounters an obstruction to its movement before it reaches a point within six or eight inches of the threshold 16, the switch 79 will be closed to energize the coil 73 and shift the armature 77 from its solid line position of FIGURE 8 into its broken line position of FIGURE 8, thereby reversing the movement of the door and reopening it again.

As indicated previously, the rocker arm 87 remains in its tripped position, after the trigger 88 is operated by the actuating member 56, until the door has again reached its fully opened position at which time the rocker arm is recocked by engagement of the nut 45 with the switch actuator 71, hence, with the element 93 of the rocker arm 87. Thus, the door cannot be closed inadvertently by closing the pushbutton switch 76, or its equivalent, while the door is being opened or in the process of being opened, after the safety switch 84 has been operated. Moreover, it will be seen that the mechanism of the invention including the rocker arm 87, the trigger 88 and related parts and switches are arranged so that the functions performed thereby cannot be overridden if the pushbutton switch is manually held closed while the door is closing. That is, pivoting of the trigger 88, whereby the rocker arm 87 is tripped from its cocked position, will open the limit switch 68 regardless of whether the pushbutton is held closed or not. Conse quently, it is first necessary to release the pushbutton switch and then close the switch again in order to effect a change in the movement of the door, and such change will result in reopening, not closing, of the door.

However, if the lower edge of the door 11 has reached a position within the six to eight inches of the threshold 16 before it encounters an obstruction, then the downward movement of the door will be stopped by the switching mechanism of the invention, in a manner described above, but the direction of movement will not be reversed. Moreover, when the door operator is again energized by the pushbutton switch 76, the movement will be upwardly toward the fully open position and not downwardly again toward the closed position.

While a manual pushbutton switch 76 has been used to. illustrate the operation of the switching mechanism of the invention, it will be recognized that switch 76 can be replaced by a radio-controlled switch serving the same purpose, namely, to electrically connect the coil 73 to the secondary of the transformer 48 for the purpose of operating the armature 77, in the manner discussed above. Also, it will be recognized that the switching mechanism of the invention can be used with a variety of mechanisms for effecting the actual movement of the door into and out of its closed position and that specific linkage, pulleys, cables, chains and so forth have been described herein in detail for illustrative purposes, only.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows.

I claim:

1. In a device including a reversible electric motor connectible to a source of electric potential for opening and closing a door connected to the motor by drive means, amechanism for controlling said motor comprising:

first circuitry means including a limit switch for connecting the motor in series with the source of potential for rotating the motor in one direction;

first means responsive to movement of said door for opening said limit switch as said door moves into one position;

second circuitry means for connecting the motor to said source for effecting rotation of the motor in the other direction;

relay means alternatively connecting said source to one of said first and second circuitry means; third circuitry means connected to said source for operating said relay means, said third circuitry means including a first normally open switch and a second normally closed switch connected in series; second means cooperating with said second normally closed switch for opening same when said door is at a selected distance from said one position;

third means cooperating with said first normally open switch for closing same when said movement of said door is interrupted before it reaches said one position; and

fourth means responsive to the interruption of said movement for opening said limit switch, whereby said motor is stopped if said second normally closed switch is open and said motor is reversed if said second normally closed switch is closed.

2. A device according to claim 1, wherein said second circuit includes a second limit switch opened by said first means when said door moves into another position; and

wherein said second normally closed switch is opened when said door is approximately in the range of from six to eight inches from said one position.

3. A device according to claim 2, including a manual, normally open control switch in parallel With said first normally open switch and said second normally closed switch for operating said relay means.

4. A device according to claim 3, including an electrically energized element connected to said source through said relay means when said second circuit is connected to said source.

5. A device according to claim 3, wherein said third circuit includes the secondary winding of a transformer having its primary winding in series with said source.

References Cited UNITED STATES PATENTS 2,737,621 3/1956 Hamilton 318-266 2,826,658 3/1958 Jackson 318-266 2,887,311 5/1959 Klamp 318-266 3,045,164 7/1962 Russell 318-266 ORIS L. RADER, Primary Examiner K. L. CROSSON, Assistant Examiner US. Cl. X.R. 

